A gaze of a user may be determined using eye tracking technology that may be calibrated to the particular user whose gaze is being tracked. Calibration of eye tracking technology may include displaying calibration points on a display. A user may fixate on the calibration point, and the eye tracking technology may calibrate based on the known locations of the calibration points and eye information present through the images captured during the calibration processes.
An example of a calibration technique is described in U.S. Pat. No. 4,950,069 to Hutchinson, which describes a sequence of calibration points displayed at known locations on the display. The user fixates on each of the calibration points while the system collects information related to the user's pupil center and glint center. Once the calibration process is completed, the system computes the coefficients of a set of linear equations that map the pupil-glint displacement to the coordinates of the screen.
While such calibration techniques increase accuracy in eye tracking technology, they involve explicit involvement from the user, which may be cumbersome and time-consuming. Furthermore, if calibration is lost (e.g., due to changes in the illumination in the environment), the user will need to stop the current activity to rerun a calibration process in order to adjust the calibration parameters.